Csi report configuration for multi-trp transmission

ABSTRACT

Certain aspects of the present disclosure provide techniques for a channel state information (CSI) report configuration for a multiple transmission reception point (TRP) transmission, such as a non-coherent joint transmission (NCJT). A method by a base station (BS) includes providing a user equipment (UE) with a CSI report configuration. The CSI report configuration is associated with one or more CSI reference signal (RS) resources. Each CSI-RS resource comprising a set of ports or port groups. The BS signals the UE to enable the UE to send a CSI report including CSI for more than one CSI-RS resource or for a CSI-RS resource comprising more than one port group and receives a CSI report from the UE.

INTRODUCTION Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, andmore particularly, to techniques for a channel state information (CSI)report configuration for a multiple transmission reception point (TRP)transmission, such as a non-coherent joint transmission (NCJT).

DESCRIPTION OF RELATED ART

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,broadcasts, etc. These wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, etc.). Examples of such multiple-access systems include3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)systems, LTE Advanced (LTE-A) systems, code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations (BSs), which are each capable ofsimultaneously supporting communication for multiple communicationdevices, otherwise known as user equipments (UEs). In an LTE or LTE-Anetwork, a set of one or more base stations may define an eNodeB (eNB).In other examples (e.g., in a next generation, a new radio (NR), or 5Gnetwork), a wireless multiple access communication system may include anumber of distributed units (DUs) (e.g., edge units (EUs), edge nodes(ENs), radio heads (RHs), smart radio heads (SRHs), transmissionreception points (TRPs), etc.) in communication with a number of centralunits (CUs) (e.g., central nodes (CNs), access node controllers (ANCs),etc.), where a set of one or more DUs, in communication with a CU, maydefine an access node (e.g., which may be referred to as a BS, 5G NB,next generation NodeB (gNB or gNodeB), transmission reception point(TRP), etc.). A BS or DU may communicate with a set of UEs on downlinkchannels (e.g., for transmissions from a BS or DU to a UE) and uplinkchannels (e.g., for transmissions from a UE to BS or DUT).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. NR (e.g., new radio or 5G) is anexample of an emerging telecommunication standard. NR is a set ofenhancements to the LTE mobile standard promulgated by 3GPP. NR isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingOFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink(UL). To these ends, NR supports beamforming, multiple-inputmultiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in NR and LTEtechnology. Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communication by a basestation (BS). The method generally includes providing a user equipment(UE) with a channel state information (CSI) report configuration. TheCSI report configuration is associated with one or more CSI referencesignal (RS) resources. Each CSI-RS resource includes a set of ports orport groups. The method generally includes signaling the UE to enablethe UE to send a CSI report including CSI for more than one CSI-RSresource or for a CSI-RS resource comprising more than one port group.The method generally includes receiving a CSI report from the UE.

Certain aspects provide a method for wireless communication by a UE. Themethod generally includes receiving a CSI report configuration. The CSIreport configuration is associated with one or more CSI-RS resources.Each CSI-RS resource includes a set of ports or port groups. The methodgenerally includes receiving signaling enabling the UE to send a CSIreport including CSI for more than one CSI-RS resource or for a CSI-RSresource comprising more than one port groups. The method generallyincludes sending a CSI report.

Certain aspects provide an apparatus for wireless communication. Theapparatus generally includes means for providing a UE with a CSI reportconfiguration. The CSI report configuration is associated with one ormore CSI-RS resources. Each CSI-RS resource includes a set of ports orport groups. The apparatus generally includes means for signaling the UEto enable the UE to send a CSI report including CSI for more than oneCSI-RS resource or for a CSI-RS resource comprising more than one portgroup. The apparatus generally includes means for receiving a CSI reportfrom the UE.

Certain aspects provide an apparatus for wireless communication. Theapparatus generally includes means for receiving a CSI reportconfiguration. The CSI report configuration is associated with one ormore CSI-RS resources. Each CSI-RS resource includes a set of ports orport groups. The apparatus generally includes means for receivingsignaling enabling the apparatus to send a CSI report including CSI formore than one CSI-RS resource or for a CSI-RS resource comprising morethan one port groups. The apparatus generally includes means for sendinga CSI report.

Certain aspects provide an apparatus for wireless communication. Theapparatus generally includes at least one processor coupled with amemory and configured to provide a UE with a CSI report configuration.The CSI report configuration is associated with one or more CSI-RSresources. Each CSI-RS resource includes a set of ports or port groups.The apparatus generally includes a transmitter configured to signal theUE to enable the UE to send a CSI report including CSI for more than oneCSI-RS resource or for a CSI-RS resource comprising more than one portgroup. The apparatus generally includes a receiver configured to receivea CSI report from the UE.

Certain aspects provide an apparatus for wireless communication. Theapparatus generally includes a receiver configured to receive a CSIreport configuration. The CSI report configuration is associated withone or more CSI-RS resources. Each CSI-RS resource includes a set ofports or port groups. The receiver is further configured to receivesignaling enabling the apparatus to send a CSI report including CSI formore than one CSI-RS resource or for a CSI-RS resource comprising morethan one port groups. The apparatus generally includes a transmitterconfigured to send a CSI report.

Certain aspects provide a computer readable medium having computerexecutable code stored thereon for wireless communication. The computerreadable medium generally includes code for providing a UE with a CSIreport configuration. The CSI report configuration is associated withone or more CSI-RS resources. Each CSI-RS resource includes a set ofports or port groups. The computer readable medium generally includescode for signaling the UE to enable the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port group. The computer readable mediumgenerally includes code for receiving a CSI report from the UE.

Certain aspects provide a computer readable medium having computerexecutable code stored thereon for wireless communication. The computerreadable medium generally includes code for receiving a CSI reportconfiguration. The CSI report configuration is associated with one ormore CSI-RS resources. Each CSI-RS resource includes a set of ports orport groups. The computer readable medium generally includes code forreceiving signaling enabling the apparatus to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port groups. The computer readable mediumgenerally includes code for sending a CSI report.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe appended drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the drawings. It is to be noted, however, thatthe appended drawings illustrate only certain typical aspects of thisdisclosure and are therefore not to be considered limiting of its scope,for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed radio access network (RAN), in accordance with certainaspects of the present disclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample base station (BS) and user equipment (UE), in accordance withcertain aspects of the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a frame format for a new radio (NR)system, in accordance with certain aspects of the present disclosure.

FIG. 7 is a flow diagram illustrating example operations by a BS forchannel state information (CSI) report configuration for multipletransmission reception point (TRP) transmission, in accordance withcertain aspects of the present disclosure.

FIG. 8 is a table illustrating example illustrating an index mapping fora jointly encoded rank indicator (RI) and CSI-RS resource indicator(SRI), in accordance with certain aspects of the present disclosure.

FIG. 9 is a flow diagram illustrating example operations by a UE forwireless communications, in accordance with certain aspects of thepresent disclosure.

FIG. 10 illustrates a communications device that may include variouscomponents configured to perform operations for the techniques disclosedherein in accordance with aspects of the present disclosure.

FIG. 11 illustrates a communications device that may include variouscomponents configured to perform operations for the techniques disclosedherein in accordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processingsystems, and computer readable mediums for a channel state information(CSI) report configuration for a multiple transmission reception point(TRP) transmission, such as a non-coherent joint transmission (NCJT).

In certain systems, a user equipment (UE) is provided with a CSI reportconfiguration. The UE may be configured with at least one CSI referencesignal (RS) resource for channel measurement. The UE may be configuredto select one CSI-RS resource for CSI reporting. The UE may report aCSI-RS resource indicator (CRI) for the selected CSI-RS resource alongwith the CSI for that CSI-RS resource. This type of CSI reportconfiguration may be useful to support single TRP (transmissionreception point) transmission. However, some systems may supportmulti-TRP transmission, such as non-coherent joint transmission (NCJT),where the CSI-RS of different TRPs may be transmitted in differentCSI-RS resources or port groups.

Accordingly, what is needed is CSI report configuration for multi-TRPtransmission.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition to,or other than, the various aspects of the disclosure set forth herein.It should be understood that any aspect of the disclosure disclosedherein may be embodied by one or more elements of a claim. The word“exemplary” is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA.SC-FDMA and other networks. The terms “network” and “system” are oftenused interchangeably. A CDMA network may implement a radio technologysuch as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRAincludes Wideband CDMA (WCDMA) and other variants of CDMA, cdma2000covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implementa radio technology such as Global System for Mobile Communications(GSM). An OFDMA network may implement a radio technology such as NR(e.g. 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX). IEEE 802.20, Flash-OFDMA, etc. UTRAand E-UTRA are part of Universal Mobile Telecommunication System (UMTS).

New Radio (NR) is an emerging wireless communications technology underdevelopment in conjunction with the 5G Technology Forum (5GTF). 3GPPLong Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTSthat use E-UTRA. UTRA. E-UTRA. UMTS, LTE. LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP), cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

New radio (NR) access (e.g., 5G technology) may support various wirelesscommunication services, such as enhanced mobile broadband (eMBB)targeting wide bandwidth (e.g., 80 MHz or beyond), millimeter wave (mmW)targeting high carrier frequency (e.g., 25 GHz or beyond), massivemachine type communications MTC (mMTC) targeting non-backward compatibleMTC techniques, and/or mission critical targeting ultra-reliablelow-latency communications (URLLC). These services may include latencyand reliability requirements. These services may also have differenttransmission time intervals (TTI) to meet respective quality of service(QoS) requirements. In addition, these services may co-exist in the samesubframe.

Example Wireless Communications System

FIG. 1 illustrates an example wireless communication network 100 inwhich aspects of the present disclosure may be performed. For example,the wireless communication network 100 may be a New Radio (NR) or 5Gnetwork. A BS 110 in the wireless communication network 100 may providea UE 120 with a channel state information (CSI) report configuration.The CSI report configuration is associated with one or more CSIreference signal (RS) resources. Each CSI-RS resource includes a set ofports or port groups. The BS 110 signals the UE 120 to enable the UE tosend a multi-TPR CSI report, for example a CSI report including CSI formore than one CSI-RS resource or for a CSI-RS resource including morethan one port group. In this case the report may include multiple rankindicators (RIs) and/or precoding matrix indicators (PMIs). The BS 110receives a CSI report from the UE 120 according to the CSI reportconfiguration.

As illustrated in FIG. 1, the wireless communication network 100 mayinclude a number of base stations (BSs) 110 and other network entities.A BS may be a station that communicates with user equipments (UEs). EachBS 110 may provide communication coverage for a particular geographicarea. In 3GPP, the term “cell” can refer to a coverage area of a Node B(NB) and/or a NB subsystem serving this coverage area, depending on thecontext in which the term is used. In NR systems, the term “cell” andnext generation NodeB (gNB or gNodeB), NR BS, 5G NB, access point (AP),or transmission reception point (TRP) may be interchangeable. In someexamples, a cell may not necessarily be stationary, and the geographicarea of the cell may move according to the location of a mobile BS. Insome examples, the base stations may be interconnected to one anotherand/or to one or more other base stations or network nodes (not shown)in wireless communication network 100 through various types of backhaulinterfaces, such as a direct physical connection, a wireless connection,a virtual network, or the like using any suitable transport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a subcarrier, afrequency channel, a tone, a subband, etc. Each frequency may support asingle RAT in a given geographic area in order to avoid interferencebetween wireless networks of different RATs. In some cases, NR or 5G RATnetworks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cells. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having an association with the femto cell(e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in thehome, etc.). A BS for a macro cell may be referred to as a macro BS. ABS for a pico cell may be referred to as a pico BS. A BS for a femtocell may be referred to as a femto BS or a home BS. In the example shownin FIG. 1, the BSs 110 a. 110 b and 110 c may be macro BSs for the macrocells 102 a, 102 b and 102 c, respectively. The BS 101 x may be a picoBS for a pico cell 102 x. The BSs 110 y and 110 z may be femto BSs forthe femto cells 102 y and 102 z, respectively. A BS may support one ormultiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. Arelay station is a station that receives a transmission of data and/orother information from an upstream station (e.g., a BS or a UE) andsends a transmission of the data and/or other information to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that relays transmissions for other UEs. In the example shown in FIG.1, a relay station 110 r may communicate with the BS 110 a and a UE 120r in order to facilitate communication between the BS 110 a and the UE120 r. A relay station may also be referred to as a relay BS, a relay,etc.

Wireless communication network 100 may be a heterogeneous network thatincludes BSs of different types, e.g., macro BS, pico BS, femto BS,relays, etc. These different types of BSs may have different transmitpower levels, different coverage areas, and different impact oninterference in the wireless communication network 100. For example,macro BS may have a high transmit power level (e.g., 20 Watts) whereaspico BS, femto BS, and relays may have a lower transmit power level(e.g., 1 Watt).

Wireless communication network 100 may support synchronous orasynchronous operation. For synchronous operation, the BSs may havesimilar frame timing, and transmissions from different BSs may beapproximately aligned in time. For asynchronous operation, the BSs mayhave different frame timing, and transmissions from different BSs maynot be aligned in time. The techniques described herein may be used forboth synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another (e.g., directly or indirectly) via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x. 120 y, etc.) may be dispersed throughout thewireless communication network 100, and each UE may be stationary ormobile. A UE may also be referred to as a mobile station, a terminal, anaccess terminal, a subscriber unit, a station, a Customer PremisesEquipment (CPE), a cellular phone, a smart phone, a personal digitalassistant (PDA), a wireless modem, a wireless communication device, ahandheld device, a laptop computer, a cordless phone, a wireless localloop (WLL) station, a tablet computer, a camera, a gaming device, anetbook, a smartbook, an ultrabook, an appliance, a medical device ormedical equipment, a biometric sensor/device, a wearable device such asa smart watch, smart clothing, smart glasses, a smart wrist band, smartjewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainmentdevice (e.g., a music device, a video device, a satellite radio, etc.),a vehicular component or sensor, a smart meter/sensor, industrialmanufacturing equipment, a global positioning system device, or anyother suitable device that is configured to communicate via a wirelessor wired medium. Some UEs may be considered machine-type communication(MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include,for example, robots, drones, remote devices, sensors, meters, monitors,location tags, etc., that may communicate with a BS, another device(e.g., remote device), or some other entity. A wireless node mayprovide, for example, connectivity for or to a network (e.g., a widearea network such as Internet or a cellular network) via a wired orwireless communication link. Some UEs may be consideredInternet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT)devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kHz and the minimumresource allocation (called a “resource block” (RB)) may be 12subcarriers (or 180 kHz). Consequently, the nominal Fast FourierTransfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 forsystem bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz),respectively. The system bandwidth may also be partitioned intosubbands. For example, a subband may cover 1.08 MHz (i.e., 6 resourceblocks), and there may be 1, 2, 4, 8, or 16 subbands for systembandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR. NR may utilizeOFDM with a CP on the uplink and downlink and include support forhalf-duplex operation using TDD. Beamforming may be supported and beamdirection may be dynamically configured. MIMO transmissions withprecoding may also be supported. MIMO configurations in the DL maysupport up to 8 transmit antennas with multi-layer DL transmissions upto 8 streams and up to 2 streams per UE. Multi-layer transmissions withup to 2 streams per UE may be supported. Aggregation of multiple cellsmay be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled. Ascheduling entity (e.g., a BS) allocates resources for communicationamong some or all devices and equipment within its service area or cell.The scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. Base stations arenot the only entities that may function as a scheduling entity. In someexamples, a UE may function as a scheduling entity and may scheduleresources for one or more subordinate entities (e.g., one or more otherUEs), and the other UEs may utilize the resources scheduled by the UEfor wireless communication. In some examples, a UE may function as ascheduling entity in a peer-to-peer (P2P) network, and/or in a meshnetwork. In a mesh network example. UEs may communicate directly withone another in addition to communicating with a scheduling entity.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A finely dashed line withdouble arrows indicates interfering transmissions between a UE and a BS.

FIG. 2 illustrates an example logical architecture of a distributedRadio Access Network (RAN) 200, which may be implemented in the wirelesscommunication network 100 illustrated in FIG. 1. A 5G access node 206may include an access node controller (ANC) 202. ANC 202 may be acentral unit (CU) of the distributed RAN 200. The backhaul interface tothe Next Generation Core Network (NG-CN) 204 may terminate at ANC 202.The backhaul interface to neighboring next generation access Nodes(NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or moreTRPs 208 (e.g., cells, BSs, gNBs, etc.).

The TRPs 208 may be a distributed unit (DU). TRPs 208 may be connectedto a single ANC (e.g., ANC 202) or more than one ANC (not illustrated).For example, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, TRPs 208 may be connected to more than oneANC. TRPs 208 may each include one or more antenna ports. TRPs 208 maybe configured to individually (e.g., dynamic selection) or jointly(e.g., joint transmission) serve traffic to a UE.

The logical architecture of distributed RAN 200 may support fronthaulingsolutions across different deployment types. For example, the logicalarchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The logical architecture of distributed RAN 200 may share featuresand/or components with LTE. For example, next generation access node(NG-AN) 210 may support dual connectivity with NR and may share a commonfronthaul for LTE and NR.

The logical architecture of distributed RAN 200 may enable cooperationbetween and among TRPs 208, for example, within a TRP and/or across TRPsvia ANC 202. An inter-TRP interface may not be used.

Logical functions may be dynamically distributed in the logicalarchitecture of distributed RAN 200. As will be described in more detailwith reference to FIG. 5, the Radio Resource Control (RRC) layer. PacketData Convergence Protocol (PDCP) layer. Radio Link Control (RLC) layer,Medium Access Control (MAC) layer, and a Physical (PHY) layers may beadaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202).

FIG. 3 illustrates an example physical architecture of a distributed RAN300, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 302 may host core network functions. C-CU 302 may becentrally deployed. C-CU 302 functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU 304 may host core network functions locally. TheC-RU 304 may have distributed deployment. The C-RU 304 may be close tothe network edge.

A DU 306 may host one or more TRPs (Edge Node (EN), an Edge Unit (EU), aRadio Head (RH), a Smart Radio Head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of BS 110 and UE 120 (as depictedin FIG. 1), which may be used to implement aspects of the presentdisclosure. For example, antennas 452, processors 466, 458, 464, and/orcontroller/processor 480 of the UE 120 and/or antennas 434, processors420, 430, 438, and/or controller/processor 440 of the BS 110 may be usedto perform the various techniques and methods described herein for a CSIreport configuration for a multi-TRP transmission, such as a NOT

At the BS 110, a transmit processor 420 may receive data from a datasource 412 and control information from a controller/processor 440. Thecontrol information may be for the physical broadcast channel (PBCH),physical control format indicator channel (PCFICH), physical hybrid ARQindicator channel (PHICH), physical downlink control channel (PDCCH),group common PDCCH (GC PDCCH), etc. The data may be for the physicaldownlink shared channel (PDSCH), etc. The processor 420 may process(e.g., encode and symbol map) the data and control information to obtaindata symbols and control symbols, respectively. The processor 420 mayalso generate reference symbols, e.g., for the primary synchronizationsignal (PSS), secondary synchronization signal (SSS), and cell-specificreference signal (CRS). A transmit (TX) multiple-input multiple-output(MIMO) processor 430 may perform spatial processing (e.g., precoding) onthe data symbols, the control symbols, and/or the reference symbols, ifapplicable, and may provide output symbol streams to the modulators(MODs) 432 a through 432 t. Each modulator 432 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. Downlink signals from modulators 432 a through 432 tmay be transmitted via the antennas 434 a through 434 t, respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) in transceivers 454 a through 454 r,respectively. Each demodulator 454 may condition (e.g., filter, amplify,downconvert, and digitize) a respective received signal to obtain inputsamples. Each demodulator may further process the input samples (e.g.,for OFDM, etc.) to obtain received symbols. A MIMO detector 456 mayobtain received symbols from all the demodulators 454 a through 454 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive processor 458 may process (e.g.,demodulate, deinterleave, and decode) the detected symbols, providedecoded data for the UE 120 to a data sink 460, and provide decodedcontrol information to a controller/processor 480.

On the uplink, at UE 120, a transmit processor 464 may receive andprocess data (e.g., for the physical uplink shared channel (PUSCH)) froma data source 462 and control information (e.g., for the physical uplinkcontrol channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a reference signal(e.g., for the sounding reference signal (SRS)). The symbols from thetransmit processor 464 may be precoded by a TX MIMO processor 466 ifapplicable, further processed by the demodulators in transceivers 454 athrough 454 r (e.g., for SC-FDM, etc.), and transmitted to the basestation 110. At the BS 110, the uplink signals from the UE 120 may bereceived by the antennas 434, processed by the modulators 432, detectedby a MIMO detector 436 if applicable, and further processed by a receiveprocessor 438 to obtain decoded data and control information sent by theUE 120. The receive processor 438 may provide the decoded data to a datasink 439 and the decoded control information to the controller/processor440.

The controllers/processors 440 and 480 may direct the operation at theBS 110 and the UE 120, respectively. The processor 440 and/or otherprocessors and modules at the BS 110 may perform or direct the executionof processes for the techniques described herein. The memories 442 and482 may store data and program codes for BS 110 and UE 120,respectively. A scheduler 444 may schedule UEs for data transmission onthe downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a wireless communication system,such as a 5G system (e.g., a system that supports uplink-basedmobility). Diagram 500 illustrates a communications protocol stackincluding a RRC layer 510, a PDCP layer 515, a RLC layer 520, a MAClayer 525, and a PHY layer 530. In various examples, the layers of aprotocol stack may be implemented as separate modules of software,portions of a processor or ASIC, portions of non-collocated devicesconnected by a communications link, or various combinations thereof.Collocated and non-collocated implementations may be used, for example,in a protocol stack for a network access device (e.g., ANs, CUs, and/orDUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device. In the second option. RRC layer 510. PDCP layer 515, RLClayer 520, MAC layer 525, and PHY layer 530 may each be implemented bythe AN. The second option 505-b may be useful in, for example, a femtocell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack as shownin 505-c (e.g., the RRC layer 510, the PDCP layer 515, the RLC layer520, the MAC layer 525, and the PHY layer 530).

In LTE, the basic transmission time interval (TTI) or packet duration isthe 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI isreferred to as a slot. A subframe contains a variable number of slots(e.g., 1, 2, 4, 8, 16, . . . , slots) depending on the subcarrierspacing. The NR RB is 12 consecutive frequency subcarriers. NR maysupport a base subcarrier spacing of 15 KHz and other subcarrier spacingmay be defined with respect to the base subcarrier spacing, for example,30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scalewith the subcarrier spacing. The CP length also depends on thesubcarrier spacing.

FIG. 6 is a diagram showing an example of a frame format 600 for NR. Thetransmission timeline for each of the downlink and uplink may bepartitioned into units of radio frames. Each radio frame may have apredetermined duration (e.g., 10 ms) and may be partitioned into 10subframes, each of 1 ms, with indices of 0 through 9. Each subframe mayinclude a variable number of slots depending on the subcarrier spacing.Each slot may include a variable number of symbol periods (e.g., 7 or 14symbols) depending on the subcarrier spacing. The symbol periods in eachslot may be assigned indices. A mini-slot, which may be referred to as asub-slot structure, refers to a transmit time interval having a durationless than a slot (e.g., 2, 3, or 4 symbols).

Each symbol in a slot may indicate a link direction (e.g., DL, UL, orflexible) for data transmission and the link direction for each subframemay be dynamically switched. The link directions may be based on theslot format. Each slot may include DL/UL data as well as DI/UL controlinformation.

In NR, a synchronization signal (SS) block is transmitted. The SS blockincludes a PSS, a SSS, and a two symbol PBCH. The SS block can betransmitted in a fixed slot location, such as the symbols 0-3 as shownin FIG. 6. The PSS and SSS may be used by UEs for cell search andacquisition. The PSS may provide half-frame timing, the SS may providethe CP length and frame timing. The PSS and SSS may provide the cellidentity. The PBCH carries some basic system information, such asdownlink system bandwidth, timing information within radio frame, SSburst set periodicity, system frame number, etc. The SS blocks may beorganized into SS bursts to support beam sweeping. Further systeminformation such as, remaining minimum system information (RMSI), systeminformation blocks (SIBs), other system information (OSI) can betransmitted on a physical downlink shared channel (PDSCH) in certainsubframes. The SS block can be transmitted up to sixty-four times, forexample, with up to sixty-four different beam directions for mmW. The upto sixty-four transmissions of the SS block are referred to as the SSburst set. SS blocks in an SS burst set are transmitted in the samefrequency region, while SS blocks in different SS bursts sets can betransmitted at different frequency locations.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

Example CSI Report Configuration for Multi-TRP Transmission

In certain wireless communication networks (e.g., new radio),non-coherent joint transmissions (NCJTs) may be used to providemultiple-input multiple-output (MIMO), multiple-user (MU) MIMO, and/orcoordinated multi-point (CoMP) communications. The NCJTs may be frommultiple transmission-reception points (multi-TRP), multiple panels(multi-panels) of a TRP, or a combination thereof. Coherent jointtransmission requires synchronization among TRPs. However, fordistributed TRPs, the precoders cannot be jointly designed and,therefore, the TRPs are not synchronized. Instead, each TRP derives theprecoder independently, without knowledge of the precoders used by theother TRPs. Thus, the joint transmission is non-coherent. Via NCJT. TRPscan transmit the same data to a UE to improve the transmissionreliability/coverage and/or the TRPs can transmit different data streamsto the UE to improve throughput. In NCJT, the TRPs may transmit a sametransport block (TB) (e.g., the same information bits although the codedbits may be the same or different).

CSI may refer to known channel properties of a communication link. TheCSI may provide explicit feedback representing the combined effects of,for example, scattering, fading, and power decay with distance between atransmitter and receiver. The CSI may provide implicit feedbackrepresenting a preferred precoder and rank to be used to transmit datastreams over the channel. Channel estimation using the pilots, such asCSI reference signals (CSI-RS), may be performed to determine theseeffects on the channel. CSI may be used to adapt transmissions based onthe current channel conditions, which is useful for achieving reliablecommunication, in particular, with high data rates in multi-antennasystems. CSI is typically estimated at the receiver, quantized, and fedback to the transmitter.

The network (e.g., a base station (BS), may configure UEs for CSIreporting. For example, the BS configures the UE with a CSI reportconfiguration (sometimes referred to as a ‘CSI report setting’) or withmultiple CSI report configurations. The CSI report configuration may beprovided to the UE via higher layer signaling, such as radio resourcecontrol (RRC) signaling. The CSI report configurations may be associatedwith CSI-RS resources for channel measurement (CM), interferencemeasurement (IM), or both. The CSI report configuration configuresCSI-RS resources (sometimes referred to as the ‘CSI-RS resourcesetting’) for measurement. The CSI-RS resources provide the UE with theconfiguration of CSI-RS ports, or CSI-RS port groups, mapped to time andfrequency resources (e.g., resource elements (REs)). CSI-RS resourcescan be zero power (ZP) or non-zero power (NZP) resources. At least oneNLP CSI-RS resource may be configured for CM.

The CSI report configuration also configures the CSI parameters(sometimes referred to as quantities) to be reported. Three codebooksinclude Type I single panel, Type I multi-panel, and Type II singlepanel. Regardless which codebook is used, the CSI report may include achannel quality indicator (CQI), a precoding matrix indicator (PMI), aCSI-RS resource indicator (CRI), and/or a rank indicator (RI). Thestructure of the PMI may vary based on the codebook. The CRI, RI, andCQI may be in a first part (Part I) and the PMI may be in a second part(Part II) of the CSI report. For the Type I single panel codebook, thePMI consists of a W1 matrix (e.g., subest of beams) and a W2 matrix(e.g., phase for cross polarization combination and beam selection). Forthe Type I multi-panel codebook, compared to type I single panelcodebook, the PMI further comprises a phase for cross panel combination.For the Type II single panel codebook, the PMI is a linear combinationof beams; it has a subset of orthogonal beams to be used for linearcombination and has per layer, per polarization, amplitude and phase foreach beam. For the PMI of any type, there can be wideband (WB) PMIand/or subband (SB) PMI as configured.

The CSI report configuration may configure the UE for aperiodic,periodic, or semi-persistent CSI reporting. For periodic CSI, the UE maybe configured with periodic CSI-RS resources. Periodic CSI andsemi-persistent CSI report on physical uplink control channel (PUCCH)may be triggered via RRC or a medium access control (MAC) controlelement (CE). For aperiodic and semi-persistent CSI on the physicaluplink shared channel (PUSCH), the BS may signal the UE a CSI reporttrigger indicating for the UE to send a CSI report for one or moreCSI-RS resources, or configuring the CSI-RS report trigger state. TheCSI report trigger for aperiodic CSI and semi-persistent CSI on PUSCHmay be provided via downlink control information (DCI). The CSI-RStrigger may be signaling indicating to the UE that CSI-RS will betransmitted for the CSI-RS resource.

The UE may report the CSI feedback based on the CSI report configurationand the CSI report trigger. For example, the UE may measure the channelassociated with CSI for the triggered CSI-RS resources. Based on themeasurements, the UE may select a preferred CSI-RS resource. The UEreports the CSI feedback for the selected CSI-RS resource.

In some systems, the UE is configured to select one CSI-RS resource forCSI reporting. This type of CSI report configuration may be useful tosupport single TRP (transmission reception point) transmission. However,some systems may support multi-TRP transmission, such as non-coherentjoint transmission (NCJT), where the CSI-RS of different TRPs may betransmitted in different CSI-RS resources or port groups. Accordingly,what is needed is CSI report configuration for multi-TRP transmission.

Accordingly, aspects of the present disclosure provide a CSI reportconfiguration for multi-TRP transmission such as NCJT.

FIG. 7 is a flow diagram illustrating example operations 700 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 700 may be performed, for example, bya BS (e.g., such as a BS 110 in the wireless communication network 100)for CSI report configuration for multi-TRP transmission.

The operations 700 may begin, at 702, by providing a UE (e.g., such as aUE 120 in the wireless communication network 100) with a CSI reportconfiguration. The CSI report configuration is associated with one ormore CSI-RS resources. Each CSI-RS resource includes a set of ports orport groups. For example, the ports of the CSI-RS resource can becategorized in multiple port groups or in one port group. If the portsof the CSI-RS resource are categorized into multiple port groups, thedifferent port groups may correspond to different QCL (quasi-colocation)configurations. In some examples, each port group associated with aparticular QCL configuration may correspond to a set of ports from adifferent TRP. In some examples, the ports for each CSI-RS resources maycorrespond to a set of ports from a different TRP. The CSI reportconfiguration may configure the UE to select/report multiple (e.g., two)CSI-RS resources or port groups. The CSI report configuration may beprovided/configured via higher layer signaling such as RRC signaling.The CSI report configuration may configure at least one NZP CSI-RSresource for CM.

At 704, the BS signals the UE to enable the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourceincluding more than one port group. Thus, the signaling enables the UEto report CSI for a multi-TRP transmission. In some examples, thesignaling may be provided with (e.g., as a part of) the CSI reportconfiguration. Thus, the UE has the flexibility to report CSI forsingle-TRP or multi-TRP.

Example Explicit Indication

According to certain aspects, the CSI for multi-TRP may be explicitlyindicated. The signaling may configure the UE to select a number (e.g.,N out of M) of the configured CSI-RS resources (e.g., an explicitlyspecified number), which may be referred to as “NCJT Type 2”. Thesignaling may configure the UE to select up to the number (e.g., up toN) of the configured CSI-RS resources (e.g., allowing the UE to selectone or more, up to the specified number), which may be referred to as“NCJT Type 1”. The number of CSI-RS resources is greater than one (e.g.,the number may be 2). In some examples, one or more new reportquantities may be added to the CSI report configuration configuring theUE to select the specified number of resources, or up to a specifiednumber of resources.

The CSI report configuration may configure the UE to report CRIindicated selected resources and RI for each of the selected CSI-RSresources or port groups. Thus, if the UE selects multiple CSI-RSresources and/or a CSI-RS resource including multiple port groups, theUE may have multiple resources to indicate in CRI and multiple RI toreport.

According to certain aspects, the definition/bitwidth/quantization ofCRI and RI may be changed. For example, a codepoint of CRI maycorrespond to a resource pair, a codepoint of RI may correspond to arank pair, and/or the CRI and RI can be jointly quantized based on aconfiguration table. Thus, the format and/or payload size of the CSI(e.g., Part I CSI) may be changed.

According to certain aspects. CRI and RI may be quantized (and reported)separately. The number of bits for the CRI may be based at least in parton a number of possible combinations of CSI-RS resources the UE canselect. A codepoint of CRI may correspond to a pair/combination of NZPCSI-RS resources. If the UE is configured for NCJT Type 2, for example,to select N out of M configured resources, the number of bits may beequal to

${\log_{2}\begin{pmatrix}M \\N\end{pmatrix}}.$

In an illustrative examples, for 3 configured CSI-RS resources, and theUE is configured to select 2 resources, then the UE could report 3possible combinations of resources: CRI=0 (resource 1, resource 2);CRI=1 (resource 1, resource 3), and CRI=2 (resource 2, resource 3). Onthe other hand, for NCJT Type 1, the number of CRI bits is

$\log_{2}{\sum\limits_{n = 1}^{N}{\begin{pmatrix}M \\N\end{pmatrix}.}}$

For example, if the UE is configured to select up to 2 out of the 3configured resources, then the UE can report 6 possible combinations ofresources: CRI=0 (resource 1); CRI=1 (resource 2); CRI=2 (resource 3);CRI=3 (resource 1, resource 2); CRI=4 (resource 1, resource 3), andCRI=5 (resource 2, resource 3).

The number of bits for the RI and the definition of a codepoint of RImay be based at least in part on a number of possible combinations ofranks for the selected CSI-RS resources or based at least in part on theCRI. A codepoint of RI may correspond to a pair/combination of ranks. Insome examples, up to rank 8 may be supported. If the UE selects a singleCSI-RS resource, then the UE may report a 3-bit RI indicating a rank 1-8for the selected resource. If two CSI-RS resources are selected, the UEmay report a 4-bit RI to indicate ten possible rank combinations for theselected resources: (1,1), (1,2), (2,1), (2,2), (3,2), (2,3), (3,3),(4,3), (3,4) (4,4), and so on. In some examples, the RI includes one ormore padding bits to keep a common bitwidth for RI for all possiblecombination of ranks in all possible resources selections. For example,because when a single CSI-RS resource is selected, the total number ofrank hypos is 8, requiring 3-bits, while if two CSI-RS resources areselected, the total number of rank hypos is 10, requiring 4-bits, then,when a single CSI-RS resources is selected a zero-padding. Moregenerally, the RI bitwidth may be based on a maximum possible bitwidth(e.g., based on the maximum number of resources that may be selected),and for any smaller bitwidth, padding bits may be included to maintainthe maximum bitwidth.

According to certain aspects. CRI and RI may be jointly quantized (andreported). Thus, the UE may report a joint indicator that indicates CRIfor the selected CSI-RS resources and the RI indicating the ranksassociated with each of the selected CSI-RS resources. The number ofbits for the joint CRI and RI is based at least in part on a number ofpossible combinations of CSI-RS resources the UE can select and numberof potential ranks for the selected CSI-RS resources. In some examples,the CRI and RI can be jointly quantized based on a table, such as theexample table 800 shown in FIG. 8. In the example shown in the table800, there are 3 configured resources and rank 8 is supported. Thus, forNOT Type 1, if the UE can select up to 2 out of the 3 resources, a 6-bitjoint indicator is used to indicate the 54 possible combinations ofresources and ranks. For NCJT Type 2, a 5-bit joint indicator is used toindicate 30 possible combinations if the UE is configured to select 2out of the 3 resources. As shown in the table 800, the differentcombinations may be associated with indices. In some examples, the table800 (or a similar table with the combinations based on the number ofconfigured resources and supported ranks) may be hardcoded in the BS andthe UE. For example, the table may be defined in the IEEE wirelesscommunication standards.

According to certain aspects, the BS provides the UE with a subset ofthe indices as a restricted set of possible combinations. The subset ofindices may be provided as a bitmap, each bit indicating whether acorresponding index is available or restricted.

Example Implicit Indication

According to certain aspects, the CSI for multi-TRP may be implicitlyindicated. The CSI report configuration configures at least one CSI-RSresource including multiple port groups. In some examples, the BS mayemulate a pair of TRPs in one CSI-RS resource by transmitting CSI-RS indifferent port groups with different QCL groups. Each QCL groupscorresponds to a group of CSI-RS ports associated with a different TRP.

If the UE selects a single CSI-RS resource and a codepoint of CRIindicates the selected resource. The CSI-RS resource may include portsof a TRP pair or a single TRP. For example, the CSI report configurationmay configure two CSI-RS resource, each with 2 port groups (e.g., twodifferent QCL groups). Thus, the UE may select a TRP pair of twocandidate TRP pairs for NCJT. In another example, there may threecandidate resources, a first CSI-RS resource with 2 ports groups andsecond and third candidate each with only one port group. Thus, the UEcan select the first resource for NCJT or the second or third resourcefor single-TRP.

According to certain aspects, the number of bits for the RI and thedefinition of a codepoint of RT is based at least in part on a number ofport groups in the selected CSI-RS resource. If the UE selects a singleCSI-RS resource with only a single port group, then the UE may send a3-bit RI (for support ranks 1-8) and if the UE selects a single CSI-RSresource with 2 port groups, then the UE may report a 4-bit RI for the 8possible combinations: (1,1), (1,2), (2,1), (2,2), (3,2), (2,3), (3,3),(4,3), (3,4) (4,4).

At 706, the BS receives a CSI report from the UE (e.g., in accordancewith the CSI report configuration). The CSI report may include CSI for amulti-TRP transmission. For example, the CRI may indicate multipleCSI-RS resources and/or a CSI-RS resource including multiple portgroups. Thus, the CSI report may include multiple RI, PMI, and CQI(e.g., one for each selected CSI-RS resource and/or port group).

FIG. 9 is a flow diagram illustrating example operations 900 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 900 may be performed, for example, bya UE (e.g., such as a UE 120 in the wireless communication network 100).The operations 900 may be complementary to the operations 700 performedby the BS.

The operations 900 may begin, at 902, by receiving a CSI reportconfiguration, the CSI report configuration being associated with one ormore CSI-RS resources, and each CSI-RS resource including a set of portsor port groups.

At 904, the UE receives signaling enabling the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourceincluding more than one port groups. Thus, the signaling enables the UEto flexibility choose a single-TRP or multi-TRP CSI report. The CSIreport configuration may configure at least one NZP CSI-RS resource forCM. The signaling may be part of the CSI report configuration. Thesignaling configures the UE to select a specified number (e.g., NCJTType 2), or up to a specified number (e.g., NCJT Type 1), of theconfigured CSI-RS resources. In some examples, the number is greaterthan one.

At 906, the UE sends a CSI report (e.g., in accordance with the CSIreport configuration). The CSI report includes at least CRI indicatingselected CSI-RS resources and RI for each selected CSI-RS resource orport group.

The CSI report may also include PMI and CQI for each of the selectedCSI-RS resources or port groups. The CRI and RI may be separately orjointly encoded. The bitwidth of the CRI and/or RI indicators may bebased on whether they are for NCJT Type 1 or Type 2, a number of theconfigured CSI-RS resources, a number of the supported ranks, and/or anumber of resources the UE can select, which define the total number ofpossible combinations for the indicators. The indicator may be based ona configured table of indices corresponding to possible combinations ofthe indicated CSI-RS resources and/or ranks. The UE may receive a subsetof indication (e.g., via a bitmap) of possible combinations from thetable, which may be reduce overhead.

In some examples, the UE only selects a single CSI-RS resource and theUE reports CRI for the selected resource. The selected CSI-RS resourcemay include more than one port group. The UE may report RI having anumber of bits based at least in part on a number of port groups in theselected CSI-RS resource.

FIG. 10 illustrates a communications device 1000 that may includevarious components (e.g., corresponding to means-plus-functioncomponents) configured to perform operations for the techniquesdisclosed herein, such as the operations illustrated in FIG. 7. Thecommunications device 1000 includes a processing system 1002 coupled toa transceiver 1008. The transceiver 1008 is configured to transmit andreceive signals for the communications device 1000 via an antenna 1010,such as the various signals as described herein. The processing system1002 may be configured to perform processing functions for thecommunications device 1000, including processing signals received and/orto be transmitted by the communications device 1000.

The processing system 1002 includes a processor 1004 coupled to acomputer-readable medium/memory 1012 via a bus 1006. In certain aspects,the computer-readable medium/memory 1012 is configured to storeinstructions (e.g., computer executable code) that when executed by theprocessor 1004, cause the processor 1004 to perform the operationsillustrated in FIG. 7, or other operations for performing the varioustechniques discussed herein for a CSI report configuration formulti-TRP. In certain aspects, computer-readable medium/memory 1012stores code 1014 for providing a CSI report configuration; code 1016 forsignaling to enable a UE for a multi-TRP CSI report, for example,allowing the UE select a number, or up to a number, of configuredresources; and code 1018 for receiving a CSI report. In certain aspects,the processor 1004 has circuitry configured to implement the code storedin the computer-readable medium/memory 1012. The processor 1004 includescircuitry 1020 for providing a CSI report configuration; circuitry 1022for signaling to enable a UE for a multi-TRP CSI report, for example,allowing the UE select a number, or up to a number, of configuredresources; and circuitry 1024 for receiving a CSI report.

FIG. 11 illustrates a communications device 1100 that may includevarious components (e.g., corresponding to means-plus-functioncomponents) configured to perform operations for the techniquesdisclosed herein, such as the operations illustrated in FIG. 9. Thecommunications device 1100 includes a processing system 1102 coupled toa transceiver 1108. The transceiver 1108 is configured to transmit andreceive signals for the communications device 1100 via an antenna 1110,such as the various signals as described herein. The processing system1112 may be configured to perform processing functions for thecommunications device 1100, including processing signals received and/orto be transmitted by the communications device 1100.

The processing system 1102 includes a processor 1104 coupled to acomputer-readable medium/memory 1112 via a bus 1106. In certain aspects,the computer-readable medium/memory 1112 is configured to storeinstructions (e.g., computer executable code) that when executed by theprocessor 1104, cause the Processor 1004 to perform the operationsillustrated in FIG. 11, or other operations for performing the varioustechniques discussed herein for a CSI report configuration formulti-TRP. In certain aspects, computer-readable medium/memory 1112stores code 1114 for receiving a CSI report configuration; code 1116 forreceiving signaling to enable the UE for a multi-TRP CSI report, forexample, allowing the UE select a number, or up to a number, ofconfigured resources; and code 1118 for sending a CSI report. In certainaspects, the processor 1104 has circuitry configured to implement thecode stored in the computer-readable medium/memory 1112. The processor1104 includes circuitry for circuitry 1120 for receiving a CSI reportconfiguration; circuitry 1122 for receiving signaling to enable the UEfor a multi-TRP CSI report, for example, allowing the UE select anumber, or up to a number, of configured resources; and circuitry 1124for sending a CSI report.

The methods disclosed herein comprise one or more steps or actions forachieving the methods. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112(f) unless the element is expressly recited using the phrase“means for” or, in the case of a method claim, the element is recitedusing the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers. DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For example, instructions for performing the operationsdescribed herein and illustrated in FIG. 7 and FIG. 9.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communication by a basestation (BS), comprising: providing a user equipment (UE) with a channelstate information (CS) repot configuration, wherein the CSI reportconfiguration is associated with one or more CSI reference signal (RS)resources, each CSI-RS resource comprising a set of ports or portgroups; signaling the UE to enable the UE to send a CSI report includingCSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port group; and receiving a CSI report from theUE.
 2. The method of claim 1, wherein: the one or more CSI-RS resourcescomprises one or more non-zero power (NZP) CSI-RS resources for channelmeasurement (CM).
 3. The method of claim 1, wherein: the signalingconfigures the UE to select a number of CSI-RS resources or up to thenumber of CSI-RS resources, of the configured one or more CSI-RSresources, for the CSI report; and the number of CSI-RS resources isgreater than one.
 4. The method of claim 3, wherein the CSI reportconfiguration configures the UE to report at least one of: a precodingmatrix indicator (PMI) or a channel quality indicator (CQI) associatedwith a rank for each of the selected CSI-RS resources or port groups. 5.The method of claim 3, wherein: the CSI report configuration configuresthe UE to report a CSI resource indicator (CRT) indicating the selectedCSI-RS resources; and a number of bits for the CRI is based at least inpart on a number of possible combinations of CSI-RS resources the UE canselect.
 6. The method of claim 3, wherein: the CSI report configurationconfigures the UE to report a rank indicator (RI) indicating ranks witheach of the selected CSI-RS resources; and a number of bits for the RIand the definition of a codepoint of the RI is based at least in part ona number of possible combinations of ranks for the selected CSI-RSresources.
 7. The method of claim 6, wherein: the RI includes one ormore padding bits to keep a common bitwidth for RI for all possiblecombination of ranks in all possible resources selections.
 8. The methodof claim 3, wherein: the CSI report configuration configures the UE toreport a joint CSI resource indicator (CRI) and rank indicator (RI), theCRI indicating the multiple selected CSI-RS resources and the RIindicating ranks with each of the selected CSI-RS resources; and anumber of bits for the joint CRI and RI is based at least in part on anumber of possible combinations of CSI-RS resources the UE can selectand ranks for the selected CSI-RS resources.
 9. The method of claim 8,wherein: the joint CRI and RI is associated with a set of indices, eachindex corresponding to a selected combination of one or more CSI-RSresources and the ranks for each of the selected combination of one ormore CSI-RS resources; and the set of indices is associated with a tablethat is hardcoded in the BS.
 10. The method of claim 9, furthercomprising: providing the UE with a subset of the indices as arestricted set of possible combinations.
 11. The method of claim 9,wherein the subset of indices is provided as a bitmap, each bitindicating whether a corresponding index is available or restricted. 12.The method of claim 1, wherein: the CSI report configuration configuresat least one CSI-RS resource comprising multiple port groups.
 13. Themethod of claim 12, wherein: the CSI report configuration configures theUE to report a CSI resource indicator (CRI) and a rank indicator (RI),the CRI indicating the selected CSI-RS resource and the RI indicatingone or more ranks associated with the selected CSI-RS resource or witheach of the port groups of the selected CSI-RS resource; and a number ofbits for the RI and the definition of a codepoint of the RI is based atleast in part on a number of port groups in the selected CSI-RSresource.
 14. The method of claim 12, wherein the CSI reportconfiguration configures the UE to report a precoding matrix indicator(PMI) and a channel quality indicator (CQI) associated with a rank foreach selected CSI-RS resource or each of the port groups of a selectedCSI-RS resource comprising multiple port groups.
 15. A method forwireless communication by a user equipment (UE), comprising: receiving achannel state information (CSI) report configuration, wherein the CSIreport configuration is associated with one or more CSI reference signal(RS) resources, each CSI-RS resource comprising a set of ports or portgroups; receiving signaling enabling the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port groups; and sending a CSI report.
 16. Themethod of claim 15, wherein: the one or more CSI-RS resources comprisesone or more non-zero power (NZP) CSI-RS resources for channelmeasurement (CM).
 17. The method of claim 15, wherein: the signalingconfigures the UE to select a number of CSI-RS resources or up to thenumber of CSI-RS resources, of the configured one or more CSI-RSresources, for the CSI report; and the number of CSI-RS resources isgreater than one.
 18. The method of claim 17, wherein the CSI reportincludes a precoding matrix indicator (PMI) and a channel qualityindicator (CQI) associated with a rank for each of the selected CSI-RSresources.
 19. The method of claim 17, wherein: the CSI report includesa CSI resource indicator (CRI) indicating the one or more selectedCSI-RS resources; and a number of bits for the CRI is based at least inpart on a number of possible combinations of CSI-RS resources the UE canselect.
 20. The method of claim 17, wherein: the CSI report includes arank indicator (RI) indicating ranks with each of the selected CSI-RSresources; and a number of bits for the RI and the definition of acodepoint of the RI is based at least in part on a number of possiblecombinations of ranks for the selected CSI-RS resources.
 21. The methodof claim 20, wherein: the RI includes one or more padding bits to keep acommon bitwidth for RI for al possible combination of ranks in allpossible resources selections.
 22. The method of claim 17, wherein: theCSI report includes a joint CSI resource indicator (CRT) and rankindicator (RI), the CRI indicating the multiple selected CSI-RSresources and the RI indicating ranks with each of the selected CSI-RSresources; and a number of hits for the joint CRI and RI is based atleast in part on a number of possible combinations of CSI-RS resourcesthe UE can select and ranks for the selected CSI-RS resources.
 23. Themethod of claim 22, wherein: the joint CRI and RI is associated with aset of indices, each index corresponding to a selected combination ofone or more CSI-RS resources and the ranks for each of the selectedcombination of one or more CSI-RS resources; and the set of indices isassociated with a table that is hardcoded in the BS.
 24. The method ofclaim 23, further comprising: receiving a subset of the indices as arestricted set of possible combinations.
 25. The method of claim 23,wherein the subset of indices is received as a bitmap, each bitindicating whether a corresponding index is available or restricted. 26.The method of claim 15, wherein: the CSI report configuration configuresat least one CSI-RS resource comprising multiple port groups.
 27. Themethod of claim 26, wherein: the CSI report includes a CSI resourceindicator (CRI) and a rank indicator (RI), the CRI indicating theselected CSI-RS resource and the RI indicating one or more ranksassociated with the selected CSI-RS resource or with each of the portgroups of the selected CSI-RS resource; and a number of bits for the RIand the definition of each codepoint of the RI is based at least in parton a number of port groups in the selected CSI-RS resource.
 28. Themethod of claim 26, wherein the CSI report includes a precoding matrixindicator (PMI) and a channel quality indicator (CQI) associated with arank for each selected CSI-RS resource or each of the port groups of aselected CSI-RS resource comprising multiple port groups.
 29. Anapparatus for wireless communication, comprising: means for providing auser equipment (UE) with a channel state information (CSI) reportconfiguration, wherein the CSI report configuration is associated withone or more CSI reference signal (RS) resources, each CSI-RS resourcecomprising a set of ports or port groups; means for signaling the UE toenable the UE to send a CSI report including CSI for more than oneCSI-RS resource or for a CSI-RS resource comprising more than one portgroup; and means for receiving a CSI report from the UE.
 30. Anapparatus for wireless communication, comprising: means for receiving achannel state information (CSI) report configuration, wherein the CSIreport configuration is associated with one or more CSI reference signal(RS) resources, each CSI-RS resource comprising a set of ports or portgroups; means for receiving signaling enabling the apparatus to send aCSI report including CSI for more than one CSI-RS resource or for aCSI-RS resource comprising more than one port groups; and means forsending a CSI report.
 31. An apparatus for wireless communication,comprising: at least one processor coupled with a memory and configuredto provide a user equipment (UE) with a channel state information (CSI)report configuration, wherein the CSI report configuration is associatedwith one or more CSI reference signal (RS) resources, each CSI-RSresource comprising a set of ports or port groups; a transmitterconfigured to signal the UE to enable the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port group; and a receiver configured toreceive a CSI report from the UE.
 32. An apparatus for wirelesscommunication, comprising: a receiver configured to: receive a channelstate information (CSI) report configuration, wherein the CSI reportconfiguration is associated with one or more CSI reference signal (RS)resources, each CSI-RS resource comprising a set of ports or portgroups; receive signaling enabling the apparatus to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port groups; and a transmitter configured tosend a CSI report.
 33. A computer readable medium having computerexecutable code stored thereon for wireless communication, comprising:code for providing a user equipment (UE) with a channel stateinformation (CSI) report configuration, wherein the CSI reportconfiguration is associated with one or more CSI reference signal (RS)resources, each CSI-RS resource comprising a set of ports or portgroups; code for signaling the UE to enable the UE to send a CSI reportincluding CSI for more than one CSI-RS resource or for a CSI-RS resourcecomprising more than one port group; and code for receiving a CSI reportfrom the UE.
 34. A computer readable medium having computer executablecode stored thereon for wireless communication, comprising: code forreceiving a channel state information (CSI) report configuration,wherein the CSI report configuration is associated with one or more CSIreference signal (RS) resources, each CSI-RS resource comprising a setof ports or port groups; code for receiving signaling enabling a userequipment (UE) to send a CSI report including CSI for more than oneCSI-RS resource or for a CSI-RS resource comprising more than one portgroups; and code for sending a CSI report.